Just purchased some used gear for my upcoming conversation.
I have a prewired control setup. With a 110v ac to 12v dc charger/converter.
I know the previous install was 144v system.
So. . Did the 110v ac charger system get power from the 144v dc system .

So. . Did the 110v ac charger system get power from the 144v dc system .

Very likely, yes.

"110 VAC" is actually 120 VAC, and has been for decades, though the old figures (including 117 VAC) live on. When AC is rectified, you get the peak value of the AC, which is about √2 times the RMS (normal AC) value, so about 120 x 1.4 = 168 V. That's about the voltage of a nominally 144 V pack when being charged (think of 12 nominally 12 V batteries at 14 V, even if the pack is actually lithium). So most chargers don't care about being fed AC or DC, as long as it has about the right peak value.

The only issue is that if the charger has a power switch, don't use it to switch off DC. It will only be rated for AC.

Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.